1. Field of the Invention
The present invention relates to an ink jet printer and an ink jet recording method, particularly to an ink jet printer and an ink jet recording method in which ultraviolet curable ink is used.
2. Description of the Related Art
As an image recording method, there has been an ink jet printer, in which ink is jetted from a recording head to a recording medium which is carried to carry out image recording.
There are serial type and line type ink jet printers. In the serial print type, a recording head is mounted on a carriage which reciprocates along a guide rail which is disposed in a direction perpendicular to a carrying direction of the recording medium, and recording is carried out while reciprocating the recording head along the guide rail. In the line head type, a recording head which is formed to have a recording range width for the recording medium is disposed in a direction perpendicular to a carrying direction of the recording medium, and recording is carried out line by line.
A recording head of the ink jet printer which is used in each type has a jet surface which faces the recording medium, and jet openings are formed on the jet surface for jetting ink.
The jet surface is in proximity to the recording medium to be carried, so that when jamming of the recording medium or the like occurs for any reason, the jet surface may contact with the recording medium and the recording head may be damaged. Thus, when such abnormality occurs in the ink jet printer, the ink jet printer stops scanning the recording head and the recording medium relatively to each other.
Recently, an ink jet printer in which ultraviolet (UV) curable ink which is cured by the UV irradiation has been used, in which an UV-rays irradiation device for irradiating the recording medium with UV-rays is provided.
However, after jetting and placing the UV curable ink onto the recording medium, when it takes a long time to irradiate with UV-rays and cure the UV curable ink, the UV curable ink may blot or change in color on the recording medium depending upon a recording environment, jetting condition of the UV curable ink or the like. Thus, in the earlier developed ink jet printer in which the UV curable ink is used, the UV irradiation device is disposed adjacent to the recording head, so that the ink is irradiated with UV-rays immediately after placing the ink to cure the ink (see, for example, Japanese Application Patent Laid-Open Publication No. 2001-310454 (p.3, FIG. 1)).
In the earlier developed ink jet printer, when abnormality such as jamming or the like occurs, even if the ink jet printer stops or stopped scanning the recording head and the recording medium relatively to each other, a light source of the UV irradiation device is kept on. Accordingly, for example, when jamming or the like occurs and the recording medium is undulated or folded, UV-rays are reflected diffusely from an irregular surface of the recording medium and the jet surface of the recording head is irradiated.
The UV-rays which are reflected diffusely and are radiated to the jet surface have intensity about three times of its normal intensity. When such the light is radiated to the jet surface, there is a problem that the ink on the jet surface and the jet opening is cured.